Spring Boot - How to Create a Deployable War

Spring boot, by default, enables you to create standalone applications through simple, minimal configurations. And due to its self-contained nature, it naturally enables building microservices.

Spring starters are poms (if using maven) that

Spring Cache - Part 5 - CacheEvict

In the Spring Cache series so far (Part1, Part2, Part3, Part4), we have seen examples where the data is getting added to the cache through the use of @Cacheable and @CachePut. But, what about removing data from cache? Consider a call to delete the record from Service or DB, in which case, we would also want to delete that record from the cache.

Deep Copy Java Objects through Serialization

When it comes to deep copy or cloning an object, the first thing that comes to mind is to override the clone() method and set each field manually. This can be pretty cumbersome to implement for complex objects or if you have to do this for a lot of them.

A simpler way to deep copy an object is to serialize it and then deserialize to get a new instance.
Let's check out a few examples.

Deep Copy using Spring's SerializationUtils

//import org.springframework.util.SerializationUtils;

 byte[] sourceInBytes = SerializationUtils.serialize(sourceInstance);
 Object newInstance = SerializationUtils.deserialize(sourceInBytes);

Since we are using java serialization here, the Class needs to implement Serializable.

Deep Copy using Apache Commons Lang SerializationUtils

//import org.apache.commons.lang.SerializationUtils
 Object newInstance = SerializationUtils.clone(sourceInstance);

Just like above example, this one needs the POJO to implement Serializable.

Deep Copy through JSON serialization

//import org.codehaus.jackson.map.ObjectMapper;
//import org.codehaus.jackson.map.ObjectMapper.DefaultTyping;
 ObjectMapper mapper = new ObjectMapper();
 String jsonSource = mapper.writeValueAsString(sourceInstance);
 MyClass newInstance = mapper.readValue(jsonSource, MyClass.class);

The advantage with JSON is that the Class need not implement a Serializable interface. It just needs to be a POJO with a public no-arg constructor and getters/setters for the properties. enableDefaultTyping here ensures that the Polymorphic Type Handling is taken care of.

Spring Cache - Part 4 - CachePut

There are scenarios, unlike retrievals, where you do not want to skip the execution of the method e.g. insert/update of a record. Such methods should not be marked as Cacheable. But, you might still want to cache the result of these methods, in order to avoid unnecessary retrievals in future calls.

Spring Cache - Part 3 - Conditional Cache

In this part of the tutorial, we will see how data can be cached conditionally. (If you haven't checked the previous parts, please visit Part 1 and Part 2. They contain sample code that the examples below refer)

Spring Cache - Part 2 - Cache Keys

In part 1 of the post, we looked at how data can be cached through simple configuration. In this part, we are going to explore the cache keys.

Spring Cache - Part 1 - Introduction

Caching is an extremely important aspect of applications that care about lower latencies. There are a multitude of rules one has to adhere to while setting up a cache, in order to optimize the performance; but not overdo it. We will not get into those details in this post. Our focus would be on what Spring provides to enable caching in your applications.

JSON Property Name Customization in Jackson using PropertyNamingStrategy

Jackson is one of the most popular java libraries for serialization/deserialization of POJOs to/from JSON. By default, Jackson derives the JSON element names from the getter/setter method names of the POJO. e.g. getActorName() is translated to actorName in the resulting JSON.